A novel, rapid and convenient competitive immunoassay for ultrasensitive detection of chloramphenicol residues in shrimp and honey was established combined with flow injection chemiluminescence. The carboxylic resin beads were used as solid phase carriers to load with more coating antigen due to their larger specific surface area and good biocompatibility. The surface of the silica dioxide nanoparticles was modified with aldehyde group to combine with more horseradish peroxidase and the chloramphenicol antibody. There was a competitive process between the chloramphenicol in solution and the immobilized coating antigen to combine with the limited binding site of antibody to form the immunocomplex. Silica dioxide nanoparticles played an important role in enhancing chemiluminescence signal, because the horseradish peroxidase on SiO2 effectively catalyzed the system of luminol-PIP-H2O2. Under optimal conditions, the chemiluminescence intensity decreased linearly with the logarithm of the chloramphenicol concentration in the range of 0.0001 to 100 ng mL-1 and the detection limit (3σ) was 0.033 pg mL-1. This immunosensor demonstrated acceptable stability, high specificity and reproducibility. The horseradish peroxidase-silica dioxide nanoparticle-chloramphenicol antibody complex successfully prepared in this article was firstly applied to the detection of chloramphenicol, and had extremely important meanings for the application of nanoparticles and enzymatic catalysis in the field of chemiluminescence.
Keywords: Carboxylic resin beads; Chloramphenicol; FI-CL competitive immunosensor; Signal amplification; Silica dioxide nanoparticle.
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